Apparatus and method for measuring depth of three-dimensional object

This application claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2022-0072580, filed on Jun. 15, 2022 in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference in its entirety herein.

The present disclosure relates to an apparatus and method for measuring a depth for a three-dimensional object.

Methods of realizing a three-dimensional (3D) image include a glasses method in which a user utilizes glasses to view a 3D image and a glasses-free method in which a user does not utilize glasses to view the 3D image. Examples of the glasses method include a polarization glasses method and a shutter glasses method. Examples of the glasses-free method include a lenticular method and a parallax harrier method. These methods allow a user to view a 3D image using the binocular parallax of both eyes. The method of realizing a 3D image for the purpose of delivering the 3D image to a viewer should deliver a realistic 3D experience that is indistinguishable from the 3D experience encountered in a natural environment to the viewer.

A 3D object encountered in a real natural 3D environment is perceived as having the same 3D depth and 3D shape regardless of the observation distance, observation point, or observation environment. On the other hand, a 3D object perceived through a 3D display device has a 3D depth and a 3D shape perceived by being systematically distorted according to the observation distance, observation point, and observation environment.

Aspects of the present disclosure provide a measuring apparatus and method for objectively quantifying and measuring perceptual distortion of a three-dimensional (3D) depth and shape induced by a current 3D display device to implement a 3D realistic image that induces the same sense of perception as that obtained from an object encountered in a natural 3D environment.

However, aspects of embodiments of the present disclosure are not restricted to those set forth herein. The above and other aspects of embodiments the present disclosure will become more apparent to one of ordinary skill in the art to which the present disclosure pertains by referencing the detailed description of embodiments of the present disclosure given below.

According to an embodiment of the present disclosure, an apparatus for measuring a depth of a three-dimensional (3D) object includes a control unit generating the 3D object by adjusting parameters of a 3D pattern, A 3D display unit displays the 3D object with a preset depth. An input unit generates an input signal based on an input received from a user. A rail extends in a front and a rear of the 3D display unit. A moving body is movable on the rail. Movement of the moving body is adjusted based on the input signal. A distance sensor measures a distance to the moving body.

According to an embodiment of the present disclosure, an apparatus for measuring a depth of a three-dimensional (3D) object includes a control unit generating the 3D object by adjusting parameters of a 3D pattern. A 3D display unit displays the 3D object with a preset depth. An input unit generates an input signal based on an input received from a user. A rail extends in a front and a rear of the 3D display unit. A moving body is movable on the rail. The movement of the moving body is adjusted based on the input signal. A distance sensor measures a distance to the moving body. The moving body is positioned at a position corresponding to a depth of the 3D object perceived by the user based on the input signal.

According to an embodiment of the present disclosure, a method for measuring a depth of a three-dimensional (3D) object includes generating the 3D object by adjusting parameters of a 3D pattern by a control unit. The generated 3D object is displayed by a display unit. A moving body is moved from a first end of a rail towards the display unit. An input signal is generated based on an input received from a user by an input unit. Movement of the moving body is stopped based on the input signal. A distance from a distance sensor to the moving body is measured when the movement of the moving body is stopped by a distance measuring unit.

The display device according to embodiments of the present disclosure may measure a degree of depth perception distortion and a degree of shape perception distortion of a 3D image.

However, the effects of embodiments of the present disclosure are not restricted to the one set forth herein, and various other effects are included in the present specification.

Embodiments of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings. Embodiments may, however, be provided in different forms and should not be construed as limiting. The same reference numbers indicate the same components throughout the disclosure. In the accompanying figures, the thickness of layers and regions may be exaggerated for clarity.

Some of the parts which are not associated with the description may not be provided in describing embodiments of the disclosure.

It will also be understood that when a layer is referred to as being “on” another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. In contrast, when an element is referred to as being “directly on” another element, there may be no intervening elements present.

Further, the phrase “in a plan view” means when an object portion is viewed from above, and the phrase “in a schematic cross-sectional view” means when a schematic cross-section taken by vertically cutting an object portion is viewed from the side. The terms “overlap” or “overlapped” mean that a first object may be above or below or to a side of a second object, and vice versa. Additionally, the term “overlap” may include layer, stack, face or facing, extending over, covering, or partly covering or any other suitable term as would be appreciated and understood by those of ordinary skill in the art. The expression “not overlap” may include meaning such as “apart from” or “set aside from” or “offset from” and any other suitable equivalents as would be appreciated and understood by those of ordinary skill in the art. The terms “face” and “facing” may mean that a first object may directly or indirectly oppose a second object. In an embodiment in which a third object intervenes between a first and second object, the first and second objects may be understood as being indirectly opposed to one another, although still facing each other.

The spatially relative terms “below,” “beneath,” “lower,” “above,” “upper,” or the like, may be used herein for ease of description to describe the relations between one element or component and another element or component as illustrated in the drawings. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the drawings. For example, in an embodiment in which a device illustrated in the drawing is turned over, the device positioned “below” or “beneath” another device may be placed “above” another device. Accordingly, the illustrative term “below” may include both the lower and upper positions. The device may also be oriented in other directions and thus the spatially relative terms may be interpreted differently depending on the orientations.

When an element is referred to as being “connected” or “coupled” to another element, the element may be “directly connected” or “directly coupled” to another element, or “electrically connected” or “electrically coupled” to another element with one or more intervening elements interposed therebetween. It will be further understood that when the terms “comprises,” “comprising,” “has,” “have,” “having,” “includes” an for “including” are used, they may specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of other features, integers, steps, operations, elements, components, and/or any combination thereof.

It will be understood that, although the terms “first,” “second,” “third,” or the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another element or for the convenience of description and explanation thereof. For example, when “a first element” is discussed in the description, it may be termed “a second element” or “a third element,” and “a second element” and “a third element” may be termed in a similar manner without departing from the teachings herein.

The terms “about” or “approximately” as used herein is inclusive of the stated value and means within an acceptable range of deviation for the particular value as determined by one of ordinary skill in the art, considering the measurement in question and the error associated with measurement of the particular quantity (for example, the limitations of the measurement system). For example, “about” may mean within one or more standard deviations, or within ±30%, 20%, 10%, 5% of the stated value.

In the specification and the claims, the term “and/or” is intended to include any combination of the terms “and” and “or” for the purpose of its meaning and interpretation. For example, “A and/or B” may be understood to mean “A, B, or A and B.” The terms “and” and “or” may be used in the conjunctive or disjunctive sense and may be understood to be equivalent to “and/or.” In the specification and the claims, the phrase “at least one of” is intended to include the meaning of “at least one selected from the group of” for the purpose of its meaning and interpretation. For example, “at least one of A and B” may be understood to mean “A, B, or A and B.”

Unless otherwise defined or implied, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which this disclosure pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an ideal or excessively formal sense unless clearly defined in the specification.

1 FIG. is a block diagram schematically illustrating a configuration of an apparatus for measuring a depth of a three-dimensional (3D) display device according to an embodiment.

1 FIG. 100 110 120 130 140 100 Referring to, an apparatusfor measuring a depth of a schematic 3D display device for measuring perceptual distortion of a 3D object may include a 3D display unit, an input unit, a measuring unit, and a control unit, In an embodiment, the apparatusfor measuring a depth of a schematic 3D display device may further include a memory.

110 110 140 The 3D display unitmay display a 3D image. For example, the 3D display unitmay display various depth stimuli by adjusting parameters of a 3D pattern according to an instruction of the control unit. In an embodiment, the parameters may include any one or more of size or spatial frequency.

120 140 120 120 130 140 The input unitreceives an input operation (e.g., an input) of a user, converts the user's input operation into an input signal and transmits the input signal to the control unit. In an embodiment, the input unitmay be implemented as, for example, a keyboard, a mouse, a touch sensor on a touch screen, a touch pad, a keypad, a voice input, and any other input processing device(s). The input unitmay receive, for example, a signal for measuring a perceived distance of a user and transmit the signal to the measuring unitor the control unit.

130 130 3 5 FIGS.to The measuring unitmeasures a perceptible depth of the user. A configuration of the measuring unitwill be described in detail with reference toto be described later.

140 100 140 110 140 140 140 130 20 FIG. The control unitcontrols the overall operation and each component of the apparatusfor measuring a depth of the 3D display device. For example, the control unitgenerates a 3D object displayed on the display unitas will be described later. The control unitgenerates the 3D object by adjusting the parameters of the pattern. In an embodiment, the parameters include a size and/or a spatial frequency of a pattern. In addition, the control unitmay adjust a depth of the generated 3D object. The control unitmay determine a maximum perceptible depth and resolution based on a measurement value of the measuring unit. This will be described in detail with reference toto be described later.

140 140 140 In an embodiment, the operations performed by the control unitmay be distributed and processed by several physically separated arithmetic and logic units. For example, in an embodiment some of the operations performed by the control unitmay be performed by a first server, and other operations may be performed by a second server. In this embodiment, the control unitmay be implemented as a sum of physically separated arithmetic and logic units.

120 130 140 The input unit, the measuring unit, and the control unitaccording to an embodiment of the present disclosure may be implemented through a nonvolatile memory configured to store an algorithm configured to control operations of various components of the apparatus for displaying the depth of the 3D display device or data about software instructions reproducing the algorithm and a processor configured to perform operations to be described below using the data stored in the non-volatile memory. In an embodiment, the memory and the processor may be implemented as distinct chips. Alternatively, the memory and processor may be implemented as a single chip integrated with each other. The processor may have the form of one or more processors.

2 FIG. is a perspective view illustrating a schematic configuration of a display unit for displaying a three-dimensional image according to an embodiment.

110 111 113 111 The 3D display unitmay include a display paneldisplaying an image and an optical layerthrough which light emitted (e.g., output) from the display panelpasses.

110 110 110 In an embodiment, in the 3D display unit, a first direction (e.g., an x direction) is a width, and a third direction perpendicular to the first direction is a length. A front surface of the 3D display unitis disposed toward a second direction (e.g., a y direction). Image display light of the 3D display unitis emitted in the second direction. However, embodiments of the present disclosure are not necessarily limited thereto.

110 110 110 110 The 3D display unitmay display an object with a positive depth that makes the object appear to the user to protrude in a front direction based on a position of the 3D display unit. In addition, the 3D display unitmay display the object with a negative depth that makes the object appear to the user to be retracted from the 3D display unit.

111 In an embodiment, the display panelmay include various flat display panels. For example, in an embodiment one of a plasma display panel, an organic light emitting display panel, an electrophoretic display panel, a liquid crystal display panel, and an electrowetting display panel may be used. However, embodiments of the present disclosure are not necessarily limited thereto.

111 111 The display panelmay include a plurality of pixels, which are minimum units for displaying an image. The display panelincludes a plurality of pixel areas in which the plurality of pixels are respectively disposed.

111 111 Each of the pixels includes sub-pixels, and a structure of the sub-pixels may be variously modified. In an embodiment, the sub-pixels may include, for example, an R (Red) pixel, a G (Green) pixel, and a B (Blue) pixel. For example, in an embodiment the display panelmay be an RGB panel in which the sub-pixels are arranged in a stripe pattern, or a pentile panel in which the sub-pixels are arranged in a diamond pattern. However, embodiments of the present disclosure are not necessarily limited thereto and the colors and arrangement of the sub-pixels may vary. For example, the display panelmay implement light rays in different directions based on the pentile panel. A general RGB panel may have a sub-pixel structure in which one pixel includes an R sub-pixel, a G sub-pixel, and a B sub-pixel having the same size. However, embodiments of the present disclosure are not necessarily limited thereto. For example, the R sub-pixel, the G sub-pixel, and the B sub-pixel included in the pentile panel may have different sizes. In one pixel, the G sub-pixel and the R sub-pixel may be disposed in a diagonal direction. In addition, in one pixel, the G sub-pixel and the B sub-pixel may be disposed in the diagonal direction. However, embodiments of the present disclosure are note necessarily limited thereto and the arrangement of sub-pixels in one pixel may be variously modified. In addition, the size and shape of each of the R sub-pixel, the G sub-pixel, and the B sub-pixel may be variously

113 111 113 113 113 113 The optical layermay be disposed in a light output direction of the display panel. For example, the optical layeris disposed in a light output direction of the plurality of pixels. The optical layermay include a plurality of lenses respectively corresponding to the plurality of pixels. However, embodiments of the optical layerare not necessarily limited thereto. For example, in an embodiment the optical layermay be a parallax barrier having a vertical slit arrangement.

111 113 113 110 110 111 A direction of a light ray output from the pixel (or sub-pixel) included in the display panelmay be determined through the optical layer. Light output from each of the sub-pixels may be emitted (e.g., output) as a light ray in a specific direction while passing through the optical layer. Through such a process, the 3D display unitmay display a stereoscopic image or a multi-view image. Optical characteristics of the 3D display unitmay include characteristics related to the direction of light rays of sub-pixels included in the display panel.

2 FIG. 113 113 1 113 2 113 110 In an embodiment as shown in, the optical layermay include a plurality of optical elements-and-. Each of the optical elements may be referred to as a ‘3D pixel’. One 3D pixel can output light rays including different information in multiple directions. For example, in an embodiment light rays in a 15×4 direction may be output from one 3D pixel included in the optical layer. However, embodiments of the present disclosure are not necessarily limited thereto. The 3D display unitmay generate an image at different points in a 3D space using the plurality of 3D pixels.

3 FIG. is a perspective view schematically illustrating a structure of an apparatus for measuring a depth of a 3D display device according to an embodiment.

3 FIG. 130 131 132 133 130 Referring to, the measuring unitmay include a rail, a moving body, and a distance sensor. In addition, in an embodiment the measuring unitmay further include a communication unit.

131 110 131 110 3 FIG. In an embodiment, the railis positioned adjacent to the 3D display unitand extends in the second direction (e.g., the y direction). Although it is illustrated in the embodiment shown inthat the railis disposed on a side surface of the 3D display unit, embodiments of the present disclosure is not necessarily limited thereto.

131 132 131 The railis provided as a guide to allow the moving bodyto move by sliding on the rail.

132 110 131 In an embodiment, the moving bodymoves forward in a direction in which the image display light of the 3D display unitis emitted or moves backward in a direction opposite to the light emission direction of the image display light along the rail.

132 132 In an embodiment, the moving bodymay stop its movement (e.g., become stationary) according to an input signal. In an embodiment, the moving bodymay also change its moving direction and/or its moving speed according to the input signal.

133 131 133 132 131 133 133 In an embodiment, the distance sensoris disposed on one end of the rail(e.g., a first end). The distance sensormay be a component for measuring a distance d between the moving bodyand the one end of the railthat the distance sensoris disposed. In an embodiment, the distance sensormay be any one of an infrared distance sensor, an ultrasonic sensor, and a laser distance sensor.

133 In an embodiment, the distance sensorincludes a transmitting unit and a receiving unit. In an embodiment, the transmitting unit emits infrared rays, ultrasonic pulses, or lasers and the receiving unit receives a reflected signal that collides with an object and is returned so that a distance is calculated based on a time difference therebetween. However, embodiments of the present disclosure are not necessarily limited thereto.

133 131 132 132 In an embodiment, the distance sensordisposed at the one end of the railcalculates the distance by transmitting infrared rays or lasers toward the moving body, and measuring the time it takes for the transmitted infrared rays or lasers to be reflected by the moving bodyand returned.

133 132 133 132 133 131 However, embodiments of the present disclosure are not necessarily limited thereto. For example, in an embodiment, the distance sensormay be attached to the moving body. In an embodiment in which the distance sensoris attached to the moving body, the distance sensorcalculates the distance by transmitting infrared rays or lasers toward one end of the railand measuring the time it takes for the transmitted infrared rays or lasers to be reflected and returned.

132 131 In an embodiment, the moving bodymay stop its movement according to the input signal, and a distance from the stopped position to one end of the railmay be measured,

120 120 140 120 130 140 1 FIG. The communication unit may receive an input signal input by the user directly from the input unitor from the input unitthrough the control unit. In an embodiment, the input unit (in) may generate an input signal according to a user's input and transmit the input signal to the measuring unitor the control unit.

4 FIG. 5 FIG. 130 130 is a perspective view schematically illustrating a structure of a measuring unitaccording to an embodiment, andis a plan view illustrating the structure of the measuring unitaccording to an embodiment.

4 5 FIGS.and 132 132 132 132 132 132 132 As illustrated in, in an embodiment the moving bodymay include a traveling body-B, a wheel-W, a driving unit-M, a controller-C, an indicator-I, and a support portion-S.

132 132 The traveling body-B that constitutes an overall main body of the moving bodymay be implemented in various structures, and in an embodiment, a structure thereof is briefly illustrated for convenience of description.

132 132 132 132 In an embodiment, the center of gravity of the moving bodymay be positioned in the traveling body-B. Accordingly, the moving bodydoes not overturn while the moving bodymoves.

132 132 1 2 132 132 132 132 5 FIG. In an embodiment a plurality of wheels-W may be disposed at a lower end of the traveling body-B, and may travel along a pair of rails Rand Rby receiving rotational driving force by at least one driving unit-M, which will be described later. Although a general example in which all four wheels-W are provided in a pair at the front and rear of the traveling body-B, respectively, is illustrated in an embodiment of, the number and arrangement position of the wheels-W are not necessarily limited thereto and may be freely changed by those skilled in the art.

132 132 132 132 132 1 132 2 132 132 5 FIG. The driving unit-M may be connected to at least one of the plurality of wheels-W, and may provide rotational driving force to drive the plurality of wheels-W. Althoughillustrates an example in which two driving units-M are connected to a pair of wheels-Wand-Wdisposed at the rear of the traveling body-B, the number and connection positions of the driving units-M are not necessarily limited thereto and may be changed freely by those skilled in the art.

132 132 132 132 132 132 132 132 132 The controller-C may be connected to the driving unit-M, and may control the driving of the driving unit-M based on a signal input through a communication unit. For example, in an embodiment the controller-C may stop the movement of the moving bodyby controlling the driving of the driving unit-M. In an embodiment, the controller-C may also change the moving direction and/or the moving speed of the moving bodyby controlling the driving of the driving unit-M.

132 132 In an embodiment, the support portion-S extends from the traveling body-B in the third direction (e.g., the z direction).

132 132 132 110 132 120 In an embodiment, the indicator-I extends from the support portion-S in the first direction (e.g., the x direction). The indicator-I is positioned to be spaced apart from the display unit. In an embodiment, the indicator-I is disposed on a straight line (e.g., in the x direction) with a virtual 3D object perceived by the subject (e.g., the user) at a point of time when the input signal generated by the input unitis received.

110 132 132 131 110 132 The display unitand the indicator-I are positioned to be spaced apart from each other in a manner so that even when the moving bodymoves forward or backward on the rail, the display unitand the indicator-I do not collide with each other.

6 FIG. 7 FIG. 8 FIG. is a schematic plan view of the apparatus for measuring a depth of a 3D display device for describing a reference distance according to an embodiment,is a schematic plan view of the apparatus for measuring a depth of a 3D display device for measuring a positive depth according to an embodiment, andis a schematic plan view of the apparatus for measuring a depth of a 3D display device for measuring a negative depth.

6 FIG. 131 Referring to, in an embodiment the user P is positioned on a straight line with one end of the rail.

0 110 A distance dbetween the user P (e.g., the subject) and the display unitis a reference distance.

1 132 110 1 132 110 1 A distance dwhen the indicator-I is positioned on a straight line (e.g., in the x direction) with the 3D display unitin the first direction (e.g., the x direction) is measured. At the distance d, the indicator-I and the 3D display unitare positioned at a same distance in the y direction to the user P. The measured value dat this time is the reference distance.

7 FIG. 110 Referring to, the 3D display unitdisplays a 3D object T having a positive depth.

110 1 The 3D object T having a positive depth is positioned so that a distance of the 3D object perceived by the user P to the user P is less than a distance from the user P to the 3D display unit(e.g., the reference distance, such as measured value d).

120 120 132 132 132 132 132 130 132 2 1 2 2 1 FIG. By receiving an input(s) from the user (e.g., manipulation of input unitby the user), the input unit (in) generates an input signal so that the moving bodymoves until the indicator-I is positioned on a straight line (e.g., in the x direction) with the 3D object in which the indicator-I is positioned at a same distance from the user P (e.g., in the y direction) as the distance of the 3D object perceived by the user. The moving bodystops the movement when the indicator-I is positioned on a straight line (e.g., in the x direction) with the 3D object T according to the input signal. The measuring unitmeasures a distance at this time between the user and the moving bodyto obtain a first measurement value d. A difference dibetween the reference distance and the first measurement value dcorresponds to a positive depth. As the difference dig between the reference distance and the first measurement value dincreases, the user perceives the 3D object as further protruding forward.

8 FIG. 110 Referring to, the 3D display unitdisplays a 3D object T having a negative depth.

110 1 The 3D object T having a negative depth is positioned so that a distance of the 3D object T perceived by the user P to the user P is greater than a distance from the user P to the 3D display unit(e.g., the reference distance, such as measured value d).

120 120 132 132 132 132 132 130 3 2 3 2 3 1 FIG. By receiving an input(s) from the user P (e.g., manipulation of the input unitby the user), the input unit (in) generates an input signal so that the moving bodymoves until the indicator-I is positioned on a straight line with the 3D object T (e.g., in the x direction) in which the indicator-I is positioned at a same distance (e.g., in the y direction) from the user P as the distance of the 3D object T perceived by the user. The moving bodystops the movement when the indicator-I is positioned on a straight line (e.g., in the x direction) with the 3D object T according to the input signal. The measuring unitmeasures a distance at this time to obtain a second measurement value d. A difference dibetween the reference distance and the second measurement value dcorresponds to a negative depth. As the difference dibetween the reference distance and the second measurement value dincreases, the user P perceives the 3D object T as protruding further backwards.

9 FIG. is a perspective view schematically illustrating a structure of an apparatus for measuring a depth of a 3D display device according to an embodiment.

Binocular parallax, which is related to depth distortion, is inversely proportional to a square of an observation distance. Therefore, an accuracy of the observation distance during measurement affects an accuracy of the measurement value.

9 FIG. 134 131 134 110 Referring to, to fix the observation distance of the user (e.g., maintain a constant observation distance), a jig portionmay be disposed on the same line (e.g., in the x direction) with one end of the railin the second direction (e.g., the y direction). In an embodiment, the jig portionmay support a chin or forehead of the user and may have a shape that opens a field of view of the user so that the user may gaze at the front of the 3D display unit. However, embodiments of the present disclosure are not necessarily limited thereto.

9 FIG. 1 8 FIGS.to 134 130 An embodiment ofis substantially the same as or similar to the embodiment ofexcept that the jig portionis further disposed in the measuring unit, and an overlapping description will thus be omitted below for economy of description.

10 12 FIGS.to are examples of a 3D object displayed on a 3D display unit according to embodiments of the present disclosure.

10 FIG. As illustrated in, in an embodiment the 3D object may be a random dot pattern.

The random dot pattern may have a pattern of a plurality of randomly arranged dots Do. According to a depth in the random dot pattern, an interval between a plurality of randomly arranged dots Do may increase or decrease in proportion to the depth.

11 FIG. As illustrated in, in an embodiment the 3D object may be a pseudorandom dot pattern.

The pseudorandom dot pattern may have a pattern in which groups having a plurality of randomly arranged dots Do are regularly arranged. According to a depth in the pseudorandom dot pattern, an interval between a plurality of randomly arranged dots Do may increase or decrease in proportion to the depth.

12 FIG. As illustrated in, in an embodiment the 3D object may be a letter, for example, the letter “E”. In an embodiment, an interval x between each horizontal stroke of the letter “E” has the same length.

13 FIG. 13 FIG. 1 12 FIGS.to is a flowchart illustrating a method for measuring 3D perceptual distortion according to an embodiment. The method for measuring 3D perceptual distortion ofis performed by the apparatus for measuring 3D perceptual distortion described with reference to.

110 In step S, the control unit generates a 3D object to be displayed by adjusting any one or more of a size or a spatial frequency of a 3D pattern.

120 In step S, the display unit displays the generated 3D object.

130 In step S, the moving body moves from one end of the rail in a direction of the display unit.

In an embodiment, one end of the rail may be positioned on a straight line with the user (e.g., in the x direction). However, embodiments of the present disclosure are not necessarily limited thereto. For example, in an embodiment, the moving body may be configured to move to one end of the rail on a straight line with the display unit. In this embodiment, the driving unit of the moving body drives the wheels according to the instructions of the controller.

140 120 120 In step S, the input unit generates an input signal according to a manipulation of the input unitby the user (e.g., an input(s) received by the input unitfrom the user). The position of the moving body at the time when the input signal is generated is positioned on a straight line with the 3D object (e.g., in the x direction) in which the 3D object is perceived by the user to be a same distance from the user (e.g., in the y direction) as a portion of the moving body, such as the indicator.

150 In step S, a distance measuring unit receives the generated input signal and measures a distance from the distance sensor to the moving body. In an embodiment, the distance sensor may be disposed at one end of the rail. In this embodiment, the distance sensor measures a distance from one end of the rail to the moving body.

140 When the input signal is not generated for a preset time in step Sfrom the user, the control unit may recognize the corresponding parameter as a depth measurement error. The depth measurement error may mean that the 3D object to which the corresponding parameter is applied is not normally recognized by the user. The preset time may be a time after the display of the 3D object.

14 FIG. 16 FIG. 17 FIG. 110 is a flowchart illustrating step Sin detail according to an embodiment, FIG. is an illustrative view for describing adjustment of a size of a random dot according to an embodiment,is an illustrative view illustrating a spatial frequency, andis an illustrative view illustrating adjustment of the spatial frequency.

14 17 FIGS.to 11 FIG. 111 Referring to, in step S, a random dot Do is generated and a size thereof is set. Although the random dot Do is generated in an embodiment, embodiments of the present disclosure are not necessarily limited thereto. For example, in an embodiment, the pseudorandom dot illustrated inmay be adopted or another image type may be generated for the 3D object. In an embodiment, in the setting of the size, the size may be reduced or enlarged according to a predefined size level, or may also be set by receiving a desired numerical value.

112 16 FIG. In step S, a spatial frequency is set for the random dot having the determined size. Here, the spatial frequency has the meaning of a frequency at which an event periodically reoccurs (e.g., an image sequence is imaged). A degree of change in pixel brightness is plotted in the form of a waveform as illustrated in.

113 In step S, a 3D object is generated by setting a depth of the random dot having a size and spatial frequency that are determined. A method of setting a depth includes, for example, a method of adjusting binocular parallax, but is not necessarily limited thereto. In the method of setting the depth by adjusting the parallax, when the parallax increases while a user's position is fixed, the depth increases.

111 112 In an embodiment, the size of the random dot Do is set in step Sand the spatial frequency of the random dot Do is set in step S. However, embodiments of the present disclosure are not necessarily limited thereto and any one of the steps may be omitted or the order thereof may be changed.

18 FIG. 19 FIG. 110 is a flowchart illustrating step Sin detail according to an embodiment, andis an illustrative view for describing adjustment of a size of a letter according to an embodiment.

18 19 FIGS.and 121 Referring to, in step S, a letter is generated and a size thereof is set. In an embodiment, in the setting of the size of the letter, the size may be reduced or enlarged according to a predefined size level, or may also be set by receiving a desired numerical value.

122 In step S, a 3D object is generated by setting a depth of the letter having a size that is determined. In an embodiment, a method of setting a depth includes, for example, a method of adjusting binocular parallax, but is not necessarily limited thereto. In the method of setting the depth by adjusting the parallax, when the parallax increases while a user's position is fixed, the depth increases.

20 FIG. is a flowchart illustrating a method for determining a depth and resolution of a 3D object according to an embodiment.

210 In step S, experimental measurement values of N persons are obtained by adjusting parameters for a 3D pattern, in which N is an integer greater than or equal to 1.

220 In step S, a pre-calculated ideal measurement value as a correct answer is compared with the experimental measurement values of N persons. In an embodiment, the pre-calculated ideal measurement value may be a result obtained by simulating a depth for a change of a parameter with respect to a pre-stored 3D pattern. Alternatively, the pre-calculated ideal measurement value may be an average of experimental measurement values of a plurality of persons.

230 In step S, an actual measurement value is obtained when the experimental measurement value is a preset correct answer rate or more. In an embodiment, the preset correct answer rate may be about 90% or more. However, embodiments of the present disclosure are not necessarily limited thereto.

240 In step S, depth and resolution corresponding to the actual measurement value obtained for the adjusted parameter are determined.

To increase reliability of the experiment, the same experiment may be repeated m times for the same user and an average thereof may be used as the experimental measurement value in which m is an integer greater than 1. In addition, to increase reliability of the experiment, the experiment may be repeated m times for n different users and an average thereof may be used as the experimental measurement value.

21 22 FIGS.and are graphs illustrating a range of perceptible depth according to a change in size and spatial frequency.

21 FIG. Referring to, a horizontal axis represents a spatial frequency, and a vertical axis represents a perceptible depth.

A white circle indicates an embodiment in which the size of the random dot is relatively small, and a black circle indicates an embodiment in which the size of the random dot is relatively large.

21 FIG. Referring to, the maximum perceptible depth according to the size of the random dot for each spatial frequency is illustrated. It may be seen that the higher the spatial frequency, the lower the maximum perceptible depth. In addition, it may be seen that an embodiment in which the size of the random dot to which the same spatial frequency is set is relatively small has a higher maximum perceptible depth than an embodiment in which the size of the random dot is relatively large.

22 FIG. is a graph illustrating a calculated ideal measurement value of depth of the 3D object and an actually measured perceive depth.

22 FIG. Referring to, it is illustrated that perception distortion decreases as a distance from a thick solid line, which is the ideal measurement value, decreases, and shape perception distortion increases as the distance from the thick solid line, which is the ideal measurement value, increases. It may be seen that the consistency of the depth of about −4 cm to about 5 cm with the thick solid line is greater than that of other depths. It may be seen that the distance from the thick solid line increases in a depth of about −5 cm or less.

23 FIG. is a graph illustrating the number of letter discrimination pixels according to a depth.

23 FIG. In, a horizontal axis represents a depth, and a vertical axis represents the number of discrimination pixels.

23 FIG. Referring to, it is possible to calculate a range value of the maximum depth in which an “F” stimulus may be clearly perceived. For example, when the depth is about −4.2 cm, a threshold value of the number of perceptible pixels is 11 pixels. In addition, when the depth is about 3.2 cm, the threshold value of the number of perceptible pixels is 11 pixels.

However, the aspects of embodiments of the present disclosure are Pot restricted to the one set forth herein.